Jerrari Cam Specs

[fiathead]

Hi Folks,

My 69 Spider has a set of Jerrari cams and I am wondering if it might make sense to swap them out for something a bit more aggressive. The car has a 40DNC14 carb, ported and polished head and headers, so it should be set up to handle a little more aggressive cam. I have been under the impression that there were a fairly aggressive set of cams in there, but looking at the specs, I am beginning to wonder now. The cams that are in there are 30-70, 70-30 cams with a 280 degree duration and .388" lift (9.8552mm). The recommended clearances on these are .008 for the intake and .010 for the exhaust. I'm running these a little wider than the Jerrari shop recommended at around .010 and .013 the last time I checked. These cams seem to be pretty mild given the rest of the mods on the engine aside from the tight clearance. Even if adjusted to the recommended .008, the lift would be less than what would be seen with a set of mild performance (40-80, 80-40) cams.

Is it worth the effort to upgrade the cams in this engine (1438) or should I just leave them be as part of the character of the car as it was in the 70s?

Thanks,
Tim

[So Cal Mark]

well I wouldn't charactize 40-80 cams as mild since the power range is 3500-7k. In my opinion you need more compression to make those cams work well. By opening your clearances you've made your cam a tad milder. I'd close them back to 008 and 010. You might consider adjustable gears and you could increase the overlap if you're looking for more top end power

[fiathead]

I'll give that a try when I adjust the valves again. I should probably invest in a set of adjustable pullys to dial it in to spec. After an engine rebuild, the machine work done could very well have things off a bit. I need to remember the advice of setting everything to correct specs before tossing parts at a problem.

[vandor]

Remember, the same cam will appear to be wilder in smaller displacement engine. While a 40-80 maybe mild in a 2 liter, it will feel like a wild cam in a 1438. I think your cams are well suited for the 1438.

[fiathead]

I had not considered it from that perspective. Thanks guys.